Film projector

ABSTRACT

A projector for projecting intelligible matter from one or two films. In order to reduce wear on the film, the film is taken from a supply reel and fed to a takeup reel by sensing arms which sense the tension in guided film loops and control supply and takeup motors to control the play out and take up of the reels.

United States Patent Inventor Richard P. Gundlach Belleville, 111.814,127 Apr. 7, 1969 Nov. 30, 1971 Gamco Industries, Inc.

Big Spring, Tex.

Appl. No, Filed Patented Assignee FILM PROJECTOR 11 Claims, 44 DrawingFigs.

Int. Cl "03b 1/00 Field 01 Search .352/166-197; 226/44; 242/188, 189,190, 75.71

[56] References Cited UNITED STATES PATENTS 2,487,476 1 1/1949 Pratt eta1. 352/180 X 2,875,667 3/1959 Chedister.... 352/180 X 2,991,022 7/1961Wallens... 242/7551 3,329,365 7/1967 Rube 352/166 X 3,347,481 11/1967Epstein et a1. .1 242/190 3,459,472 8/1969 Husted et a1 353/173 XPrimary Examiner-S. Clement Swisher Attorney-Kingsland. Rogers,.Ezell,Eilers and Robbins ABSTRACT: A projector for projecting intelligiblematter from one or two films. In order to reduce wear on the film, thefilm is taken from a supply reel and fed to a tukeup reel by sensingarms which sense the tension in guided film loops and control supply andtakeup motors to control the play out and take up of the reels.

PATENTED man 1911 SHEET 3 OF 9 figja.

IN VEA/TOQ: RICHARD P. GUNDLACH FILM PROJECTOR BACKGROUND OF THEINVENTION In the past, visual training projectors have been devised suchas those shown in Stoyanoff U.S. Pat. No. 2,775,827 and Kropp U.S. Pat.No. 2,986,968. Such projectors are devised to present a pair of filmstrips in overlapping relationship before a projector lampforsimultaneous projection upon a viewing screen. One of the film strips,known as a text film, consists of successive frames upon which readingmatter is photographed, and the other film strip, referred to as thefixation film, consists of successive frames, which may be alternatelyfully opaque and wholly transparent, whereby timed, momentary projectionof a frame of text in the projection aperture is achieved by feeding theoverlapping fixation film strip through a transparent frame at apredetermined rate. The fixation film strip may also consist ofsuccessive frames, which are partially opaque and partially transparent,with the ratio of the areas of the transparent and opaque portions beingincrementally varied in successive frames, so as to provide a steppedformation along the film strip, whereby successive portions of thematter on the text film are sequentially exhibited or masked to providesuccessive fixations for reading training as the fixation film is fedstep-by-step through the projection aperture with relation to the textfilm. In this way the readers eye is trained and guided at desired ratesof speed on the projected film.

The film feeding means for the projector include a pair of solenoids,one solenoid for each of the front and rear film strips. The solenoidsare energized intermittently to'operate through a forward and returnstroke, and each is arranged to drive by engagement through sprocketopenings one of the films one frame during a forward stroke. Thefrequency of the intermittent feeding motion is controlled by thecontrol system, which varies the frequency of the operation of thesolenoid to a rate desired by the operator.

Such visual training projectors as described above have been limitedwith respect to their projection capabilities to restrict in one planeof projection either horizontal or vertical. Further, wear and tear onthe film has been provided through the usual sprocket arrangement tosupply the film from the supply reel and to feed up on the takeup reel.Further, the shuttle feeding system has been restricted throughenergization of the solenoid because of the type of movement required ofthe shuttle in advancing the film. Difficulties have also arisen inloading the front and the rear film in the projector which has entaileda laborious and time consuming operation. Likewise, timing of the frontand the rear film has been difficult, because of the exactness requiredfor satisfactory operation. Additionally, the projectors have beenlimited to uniformly wound film. 1

SUMMARY OF THE INVENTION By means of this invention there has beenprovided a visual training projector which can be used as motion pictureprojector with a single film, or as a visual training projector withfront and rear films provided for fixation. The projector is adapted toproject in either a horizontal or a vertical plane providing a greaterdegree of adaptability for presentation of the projected film forvarious purposes. This is accomplished by the relationship of a tiltedlamp and blower channel, enabling the projection to be rotated 90clockwise in a vertical and a horizontal position, and the two sets offeet which are adjustable by a common adjustment mechanism to providesupport in either the vertical or horizontal position with tiltadjustment in either position. Through the relationship of the blowerchannel with the projector lamp, air is blown upwardly regardless of thehorizontal or vertical position.

To obviate wear on the film in the conventional sprocket operation inthe sprocket holes of the film to provide supply and takeup from thefilm reels, sensing arms are employed. These sensing arms connect with asupply reel of film and a takeup reel, and by connection to motorswitches, over or under feeding of the film is controlled. Thus, thesensing arms are employed to actuate motors to drive the supply and takeup wheel spindles to insure that the proper amount of film is fed to theapparatus at the proper rate and thereby eliminates wear and tearprovided in the sprocket and the sprocket holes of the filmconventionally used in the past.

In the film feeding means, past the projector lens, a shuttle mechanismis employed utilizing a single ball pivot. The shuttles are actuated bya single and common cam, and pivoting back and forth is provided throughthe ball pivot to insure two directions of freedom in the holding andactuation of the shuttle.

Feeding of the film is facilitated for both the front and the rear filmsthrough solenoid operated film gates. The pressure plates which guidethe film are controlled by solenoids which, upon operation, disengagethe pressure plates and provide a free space for ready insertion orremoval of the film.

The projector is additionally provided with both clockwise orcounterclockwise film wound capability. Conventional projectors in thepast have required the film to be wound in a particular direction sothat the projector can be properly operated utilizing so-called A or Bwinding of film. A particular spindle design provided in this inventionmakes it possible to operate either clockwise or counterclockwise woundfilm. Motor reversal is provided for the film supply in order toaccomplish the capability for clockwise or counterclockwise wound filmas well as rewinding.

The circuitry employs photocell timing which insures a high degree ofaccuracy in the operation of the apparatus. Cuing is effected to a highdegree of accuracy through remote control in the operator's handle,which has a complete control switching system to effect operation at aremote point from the apparatus.

The above features are objects of this invention and further objectswill appear in the detailed description which follows and will beotherwise apparent to those skilled in the art.

For the purpose of illustration of this invention, there is shown in theaccompanying drawings a preferred embodiment thereof. It is to beunderstood that these drawings are for the purpose of example only, andthat the invention is not limited thereto.

In the drawings:

FIG. 1 is an end elevation of the equipment shown in carrying positionand resting on a work surface;

FIG. 2 is a view in right end elevation of FIG. 1 showing the controland power cords extended in dotted lines;

FIG. 3 is an enlarged plan view of the hand control assembly;

FIG. 4 is a view in side elevation of the assembly of FIG. 3;

FIG. 5 is a view in end elevation of the apparatus with the coverremoved;

FIG. 6 is an enlarged top plan view of the equipment with the coverremoved;

FIG. 7 is a view in end elevation of the assembly of FIG. 6;

FIG. 8 is a view in section taken on the line 8-8 of FIG. 6;

FIG. 9 is a view in section taken on the line 9-9 of FIG. 8 showing thebottom structure of the equipment;

FIG. 10 is a view in section taken on the line 10-10 of FIG. 9 with thetop cover in place;

FIG. 11 is an enlarged fragmentary view of a portion of FIG. 10 showingthe cover and base hook up;

FIG. 12 is a view in section taken on the line l2l2 of FIG.

FIG. 13 is a view taken in section on the line 13-13 of FIG. 9 showingthe shuttle structure and cam power assembly;

FIG. 14 is a view taken in section on the line l4l4 of FIG. 9 showingthe lamp and blower structure;

FIG. 15 is a plan view of the inside of the bottom case;

FIG. 16 is a view in section taken on the line 16-16 of FIG. 15 showingthe assembly elevating mechanism;

FIG. 17 is a detailed view showing the linkage for the elevatingmechanism;

FIG. 18 is an enlarged vertical sectional view taken on the line l8-l8of FIG. 17;

FIG. 19 is a front elevation of the left hand shuttle and cam powerstructure;

FIG. 20 is an end elevation taken from the left side of FIG. 19partially in section;

FIG. 21 is a view in elevation cam power structure;

FIG. 22 is a view in side elevation taken from the right side of FIG. 21with the supporting structure partially in section;

FIG. 23 is a view in front elevation of the front solenoid pivotstructure;

FIG. 24 is a view in side elevation taken from the right side of FIG. 23partially in section;

FIG. 25 is a view in vertical section showing the supporting structure'for the filler reel spindle;

FIG. 26 is a top plan view of the film reel takeup spindle;

FIG. 27 is a view in section taken on the line 27-27 of FIG.

of the right hand shuttle and FIG. 28 is a view in elevation of thesensing arm and switch structure;

FIG. 29 is a view of the sensing arm and switch structure taken from theleft side of FIG. 28;

FIG. 30 is a side view of the sensing arm and switch structure-takenfrom the right side of FIG. 28 with the wiring omitted;

FIG. 31 is a view in side elevation of the rear solenoid assembly forthe operation of the rear shuttle, partly broken away and insections inthe center portion;

FIG. 32 is a view in front elevation of the rear solenoid assembly;

FIG. 33 is a view in side elevation of the front solenoid assembly,partly broken away and in vertical section of the center portion thereoffor the operation of the front shuttle;

FIG. 34 is a view partly in longitudinal section of the front solenoidassembly for the operation of the front pressure plate;

FIG. 35 is a view in front elevation of the front solenoid assembly;

FIG. 36 is a top plan view of the front pressure plate;

FIG. 37 is a view in front elevation of the front pressure plate;

FIG. 38 is a view in front elevation of the rear solenoid assembly forthe operation of the rear pressure plate;

FIG. 39 is a view in side elevation of the rear solenoid assembly takenfrom the right side of FIG. 38;

FIG. 40 is a top plan view of the rear pressure plate;

FIG. 41 is a view in front elevation of the rear pressure plate;

FIG. 42 is a left half of a circuit diagram of the electrical componentsof the apparatus;

FIG. 43 is the right half of the circuit diagram; and

FIG. 44 is a fragmentary plan view showing a typical front text film atthe top and a rear fixation film used in reading training.

DESCRIPTION OF THE INVENTION Referring now to the drawings, theprojector is generally indicated by the reference numeral 50 in FIGS. 1,2, and 5. It is provided with an electrical cord 52 adapted to beattached to a convenient source of AC current and an operators handle54, connected by cord 56 through the projector for remote controloperation.

The remote control handle 54 is provided with an on-off projector switch57, a rear-front film selector switch 58, and a reverse forward switch60 for the film. An on-off cue-switch for cuing purposes, designated bythe numeral 62, likewise is provided. Additional control switches are astart switch 64, a stop switch 66, speed control switch 67, and singleframe switches for the rear film 68 and the front film 70. A viewingwindow 71 is provided to show the speed control setting. A functionswitch 72 is mounted on the projector operable to Off, Run, Rewind, andLoad positions.

The projector 50, as shown in FIGS. 1, 2, 5, 10, 11 and 14 through 18,is provided with feet 74, for a vertical projection, and feet 76 forhorizontal projection. Supporting structure for the projector includes ahousing 80, which is open topped and closed by a horizontal support base82. A cover 84 provides for protection of the apparatus and a handle 86facilitates carrying of the projector as a portable unit.

A main motor 90 is mounted upon a top plate and is provided with a shaft92, connected to a twin blower unit 94, provided with a stator casing 96and a bladed rotor 98 eccentrically mounted in the stator. Air is blownthrough channel 100 through a chimney 102 located at a 45 angle to thelamp housing 103, as best shown in FIG. 14. The chimney 102 houses aprojector lamp 104 to provide a source of light to the film aperture toprovide for projection through lens 106, as will be further described.The 45 tilted relationship of the chimney 102 insures that air is blownupwardly, past the lamp, at a 45 relationship regardless of whether theprojector is in the horizontal position, as shown in FIG. 14, or rotated90 clockwise to provide for vertical projection as in FIG. 5. A shutter108 having four vanes 110 is mounted on a shaft 112. The shaft isjoumaled in a bearing block 114 supported from the top plate. The shaftis powered by a pulley 116, connected by a pulley belt 118 to a pulley120 mounted on the main motor shaft 92, as best shown in FIG. 13.

FILM ADVANCING MEANS A supply spindle 122, receiving a supply roll offilm shown in dotted lines in FIG. 6 by the reference numeral 124, isconnected to a reversible motor 126 having a split field coil 127through conventional gear reducing mechanisms. The film is fed throughpath 128, as best shown in FIG. 6, past idlers I30 and 132, and sensingguide 134 to film gate and advancing assembly 136 where film shuttleadvancing means is provided, as will be further described hereinbelow.The film is then fed in path 138, past a takeup arm sensing guide 140,idler roller 142 and then to a takeup reel, indicated in dotted lines byreference numeral 144, which is connected to take up spindle 146. Thetakeup spindle shaft is connected by suitable reducing gear mechanism totakeup reversible motor 148 having a split field coil 147, as best shownin FIG. 13.

The supply film sensing guide 134 and the takeup film sensing guide areidentical in construction and are shown in FIGS. 28, 29 and 30. Thesupply sensing guide is comprised of a sensing arm 149, provided with aroller 150, around which the film passes as shown in FIG. 6. The sensingarm 149 is pivotally mounted upon a cam shaft 152, joumaled in amounting bracket 154, connected to the underside of the base 82. Aneccentric reel 156 is connected at the periphery to a cable 158, which,in turn, is connected to a biasing spring 160 anchored by a bolt 162 tothe underneath side of the base, as shown in FIG. 9, to bias the sensingarm 149 to the position shown in FIG. 6, while permittingcounterclockwise movement as viewed in FIG. 6 when tension upon the filmmoves the sensing arm. A cam 164 is fixed to the shaft 152 and isadapted to actuate a microswitch 166, as best shown in FIGS. 28 and 29.The microswitch arm of switch 166 is adapted to depress a switch elementto close a circuit to the split field supply motor to actuate it andfeed out additional film in order that the film be supplied to theaperture and advancing means 136 without tension to prevent strain andwear upon the film.

A similar switch 168 is provided on the opposite side of earn 164, asshown in FIG. 28, and operates similarly to switch 166 to reverse thesupply motor. The takeup sensing guide 140 operates in a like manner toprevent strain or pull upon the film in the path 138. Thus, the guide140, by means of the sensing arm and cam 169 and switches 170 and 172,operates in a similar fashion through the use of identical parts. Thetakeup motor associated with the takeup reel 144 is arranged byappropriate circuitry of the switches 170 and 172, later to bedescribed, to run the split field takeup motor forward or reverse,depending on the direction of film motion selected and the size of thefilm loop, which causes the sensing arm 149 to move in the clockwise orcounterclockwise direction, as viewed in FIG. 6.

APERTURE AND FILM ADVANCING MEANS The reading film 125 and fixation film129, shown in FIG. 44, are provided with a series of holes 180, whichare adapted to be engaged by the shuttle claws used for advancing thefilm past the aperture and film-loading gate, generally identified byreference numeral 182 in FIG. 6. The aperture gate provides a gate forthe film and incorporates a film guide plate 184, forming no part ofthis invention, and for which reference may be had in Kropp et al. US.Pat. No. 2,986,968. The guide plate is provided with conventional filmguide grooves receiving the front and rear films, and is provided with afront pressure plate 186 and a rear pressure plate 188, as shown inFIGS. 6 and 36,

, 37, 40 and 41. These pressure plates are similar in construction tothe conventional pressure plates shown in the Kropp et al. U.S. Pat. No.2,986,968, but are provided with hinge pins in order that they may berapidly operated by solenoids to open the film gate for ready insertionand removal of the film in the feeding operation. Thus, the frontpressure plate 186 is provided with a conventional aperture 190 and aslot 192 receiving the shuttle claw for advancing the film throughengagement in the notches 180. The rear pressure plate 188 is providedwith a similar aperture and slot. The front pressure plate is furtherprovided with hinge pins 194, which are received within a journal in theguide plate. Likewise, the rear pressure plate 188 is provided withhinge pins 196 joumaled in a similar fashion. The hinge pins for thefront and rear pressure plates provide for a pivotal movement about thepins when the pressure plate solenoids are operated to open the pressureplate in the film gate.

The front pressure plate 186 is operated by a front solenoid 198, bestshown in FIGS. 34 and 35. The front solenoid for operating the frontpressure plate in the film gate is housed within housing 200. Thesolenoid for the rear pressure plate is identified by the referencenumeral 202 in FIGS. 38 and 39, and is supported upon support plates 114depending vertically from the base as shown in FIG. 9. The solenoidarmature is connected to an elongated hooked member 204 with the hookedend 206 fitting around the pin 208 provided on the pressure plate 188.Upon operation of the solenoid, the vertically and upstanding hookedmember 204 causes a rocking and opening of the rear pressure platethrough a swinging or pivoting movement around its hinged pins 196.

SHUTTLE ASSEMBLY The front shuttle for operating the front film isidentified by the reference numeral 210 in FIG. 21. This shuttle isprovided with a claw 212 at the top adapted to engage in the hole 180 ofthe film 125 to move it past the film gate. The shuttle is providedfurther with a cam follower 214 engageable by cam 216, which is mountedupon the shaft 112, as best shown in FIG. 10. The shuttle is pivotedback and forth in an arclike direction by the cam 216, through a pivotalmounting on a ball pivot 218, as shown in FIG. 22. Thus, the bottom ofthe shuttle 210 is provided with a hemispherical depression 220, whichseats the ball 218 in a bearing plate 222. The shuttle 210 is biasedinto engagement with the cam by means of a biasing spring 224 connectingthe front shuttle 210 to rear shuttle 226 shown in FIGS. 10 and 19. Thebiasing spring is hooked to support 228 on the front shuttle and 230 onthe rear shuttle.

The rear shuttle 226 is constructed in a similar fashion having anidentical pivotal arrangement and similar reference numerals areemployed for the identical construction. Through the operation of thecam, the front and rear shuttles are caused to pivot back and forth inan arclike manner in the plane of the film as it passes through the filmgate. The film engaging claws 212 are received and move back and forthwithin the notches 192 of the front and rear pressure plates. The frontshuttle 210 is engaged and disengaged with the film by a solenoid toeffect perpendicular movement with respect to the plane of the film. Thefront solenoid is indicated by the reference numeral 234 in FIG. 33 andis shown mounted on the bottom of the base plate in FIG. 9. The solenoidis provided with an armature 236, which is connected to a shuttleoperating arm 238 as shown in FIGS. 12, 23 and 24. The armature fitsthrough opening 240 and is connected to the arm 238 by spring pressureplates 242. The arm 238 is pivoted by pivot pin 244 to a trunnion 246mounted upon vertical support plate 248, as shown in FIG. 12. The upperend of the shuttle operating arm 238 is provided with a yoke 250 whichis received within the opening 252 of the shuttle.

The rear shuttle 226 is operated by rear solenoid 254, shown in FIG. 31.This solenoid is mounted to the bottom of the base in a similar fashionto that employed for the front solenoid. The rear solenoid has anoperating armature 256 provided with a yoke at the end, designated bythe reference numeral 258, which fits within the opening 252 of the rearshuttle to provide for its movement into and out of engagement with therear film to engage the rear shuttle claw with the advancing notches forthe rear film.

THE FILM REEL SPINDLES The supply film reel spindle 122 is best shown inFIG. 25. It includes a dog 260 adapted to be turned a quarter turncounterclockwise and to the left, as shown in FIG. 25, through detents262 and 264, which engage a spring biased ball 268. In loading the film,the dog 260 is left in the vertical position to roll out film forthreading.

The takeup spindle 146 is best shown in FIGS. 26 and 27. As there shown,it is provided with a shaft 270 having a squared bottom portion and acylindrical upper portion. A reel retainer 272 is provided comprising aspring biased ball 274 seated in the bottom of the shaft. This shaft isfurther provided with a conventional friction clutch (not shown).

TILT MECHANISM The tilt mechanism to provide for adjustment of theprojector in both the vertical position and the horizontal position isgenerally identified by the reference numeral 280 in FIGS. 15 through18. It includes an adjustable vertical table engaging support bracket282 and a horizontal bracket 284, which, depending upon the position ofthe projector, are adapted to be used as an adjustable base. The tiltingmechanism is spring biased by means of a spring 286 connected at one endto post 288 mounted on the housing 80, and at the other to an operatingarm 290 mounted on a trunnion portion 292. The operating arrn 290 urgesa shaft 293, connected to the vertical bracket 282, to the left asviewed in FIG. 16. The operating arm 290 is T-shaped and has a legconnected to a shaft 294 urging the horizontal bracket 284 to the bottomas viewed in FIG. 16. A lock shaft 295 is adapted to bind a collet 296against the shaft 293 to set the adjustment mechanism to the desiredposition. .loumaling of the shaft 294 is provided by a journal 297 andjournaling for the shaft 293 is provided by a journal 298 mounted upon amounting plate 299 connected to the base 80. The journal 298, as shownin FIGS. 15 and 16 receive the collet in a medial slot.

For the operation of the tilt mechanism, the locking shaft 295 is firstloosened, the projector supported on feet 74 or 76 is then tilted to thedesired elevation, and the lock shaft 295 is tightened to bind thecollet 296 against the shaft 293, which locks the tilt mechanism insecure position. The spring biasing, effected through the spring 286,urges the bracket 282 and 284, depending upon whether the projector isin vertical or horizontal position, into engagement with the supporttable top or other base.

THE ELECTRICAL CIRCUIT The principal function of the circuits is toprovide properly timed pulses to rear and front shuttle solenoids 198and 234, respectively. These pulses cause the solenoids to pull theshuttle teeth into engagement with the film sprocket holes 180 andadvance the film one frame for each pulse, in a direction which isdetermined by timing of the pulse with respect to the mechanicalposition of the shuttle cam 216.

Timing pulses, which differ by 180 of rotation of the cam, are switchselectable to provide for film transport in forward or reversedirection. These timing pulses, which occur once for each revolution ofthe main shaft, are divided to lower frequencies providing 18 differentoperating speeds ranging from one pulse per second to 24 pulses persecond providing corresponding frame rates for the film transport. Meansare included for gating a single pulse to the shuttle solenoid, whenmanually actuated by depressing a button. The resulting film frameadvance is provided for both the front and rear shuttle solenoids. Anadditional function of the electrical circuits is to provide control offilm motion by means of transparent cue spots 300 printed on the film inthe area normally occupied by the sound track. When a cue appears on thefront film, the resulting light transmission stops all film motion, bothfront and rear. When a cue appears on the rear film, the front film willmove along with the rear film, one frame for each rear film cue.Automatic spooling of the film from supply and takeup reels is providedby two reel drive motors 126 and 148,

respectively, controlled by the spring-loaded sensing guides 134 and140, which determine the size of the film loops and operate the reelmotors accordingly to maintain essentially constant loops of filmbetween the supply and takeup reels and the film transport mechanism. Arewind function is included which provides means for rewinding film fromthe takeup reel back onto the supply reel ready for subsequent reuse.Operation of the circuit shown in FIGS. 42 and 43 in detail is asfollows:

Nominal 117 volt AC power is applied through power cord 301 to connector302 and 304. From pin of 304 this voltage is applied to fuse 306. Theother side of the line from pin 6 of connector 304 is connected toterminal 1 of autotransformer 308. The load side of the AC fuse 306 isconnected to the wiper of function switch 72, section B. As shown, inthe off position, this wiper is connected to an unused terminal 1 of theswitch, therefore no AC power is applied anywhere within the circuitswith function switch 72 in the OFF, or number one position as shown.When this switch is placed in the load position on terminal 2, AC powerfrom the wiper of section B is applied to terminal 4 of autotransformer308. Note that in positions 3 and 4 of the switch, the Run and Rewindpositions, this voltage is also applied to terminal 4. Thus, thetransformer 308 will be energized whenever the function switch is in anyof its three operating positions, load, run, or rewind on terminals 2, 3and 4. Pilot lamp 312 is connected in parallel with terminals 1 and 4 ofthe transformer and indicates the application of voltage to thetransformer. The transformer provides 26 .volts AC between its terminals1 and 3. These terminals are connected to the input terminals of abridge rectifier 314 consisting of unidirectional diodes 316, 318, 320,and 322 in the power supply assembly 323. The output of this bridgerectifier is filtered by condenser 324 and provides approximately 28volts DC to power circuits within the equipment. The negative side ofthe bridge output, the junction of diodes 316 and 320, is connected toone side of load solenoids 198 and 202. For convenience throughout thediscussion of the circuit functions, and in accordance with standardpractice, this negative output of the power supply will be referred toas DC common. The filtered positive output available at the junction of318 and 322 is protected by a DC fuse 326, and applied to the wiper ofthe function switch 72, Section A. With this switch in the loadposition, 28 volts DC is applied across the load solenoids. Thesesolenoids retract the front and rear pressure plates 186 and 188allowing the film to be loaded into, or removed from the film gates.When the function switch is placed on terminal 3, the RUN position, this28 v DC is applied from section A, terminal 3, through pin 9 ofconnector 328, pin L of cable 330, to a tenninal of projector ON-OFFswitch 56, located on the remote control unit 54. When this switch isplaced in the ON position, 28 volts DC is supplied back through pin K ofcable 330, through pin 8 of connector 328, to the upper terminals offront and rear shuttle solenoids 234 and 254, respectively, to one sideof the timing lamp 332 through resistor 334, to terminal 1 of the powerrelay 336, and to terminal 7 of the power supply 323. The function ofthe remaining components in the power supply is to regulate and filterthe 28 volt input applied at terminal 7, and provide outputs of 8, l8,and 5 volts. This is accomplished with a series regulating transistor338, a reference diode 340, resistors 342 and 344, and capacitor 346,which provide an 18 volt output. Resistors 348 and 350 and diode 352 inthe power supply, and diode 340 in the main circuit board assembly 362provide 5 and 8 volt outputs. With switch 56 in the remote control unitin the ON position, and function switch 72 in the Run position, thetiming lamp 332 illuminates, power supply output voltages appear, thepower relay 336 is energized, and the shuttle solenoids 234 and 254 havevoltage applied to their upper terminals. Energizing the power relay 336supplies 21 volts AC from transformer 308 terminals 1 and 2 toprojection lamp 104, and completes the circuit for volts AC throughcontacts 7 and 10 to the main drive motor 90. This 120 volts AC is alsoapplied through terminal 3 of section C of the function switch to thewiper of this section and then to the takeup and supply reel motorarmatures 148 and 126, respectively. (BLK leads) SINGLE FRAME OPERATIONAssume the switches in the remote controller unit 54 are set as follows:

Cue switch 62 is ON. Single front switch 70 is not depressed. SingleRear switch 68 is not depressed. Start switch 64 is not depressed. Stopswitch 66 is not depressed. The ON- OFF switch 56 has been placed in theON position. FOR.- REV. switch 60 is in the FOR. position and rear frontswitch 58 is in the front position. Under these conditions a singleframe of film may be moved in the forward direction by depressing eitherthe single front or single rear push button. Assume the single frontswitch is depressed. The regulated plus 18 volts from the power supplyis supplied to the common terminal of this switch. Depressing it willcause this 18 volts to be applied through the normally open contact (NO)to pin Y of connector 358, where it passes through the cable 330 and isapplied through pin 1 of connector 304 in the circuit board 362. Thisprovides a positive voltage through resistor 364 to terminal 5 of gate366. In addition, this positive voltage is applied through diode 368 andcapacitor 370 and diode 372 to the base of transistor 374. Thistransistor and transistor 376, along with resistors 378, 380, 382 and384 make up a monostable multivibrator with an output appearing at thecollector of diode 376, which is a positive pulse of voltage whoseduration is normally in excess of 30 milliseconds. In the stable state,transistor 374 is conducting heavily by virtue of the base currentprovided through resistor 380. The positive pulse applied through diode372 momentarily reduces transistor 374 base current to zero, thusreducing the collector current to zero and causing the voltage dropacross resistor 378 to go to zero, therefore the collector potential oftransistor 374, which had been approximately 5 volts positive, now goesto zero, causing a heavy flow of base current through transistor 376,causing it to conduct heavily, increasing the drop across resistor 382to approximately 5 volts. This positive 5 volts is applied to the baseof transistor 388, a common collector amplifier used to isolate themultivibrator output from its load. Duration of the output pulse isdetermined primarily by resistor 380 and capacitor 386. The positiveoutput from this multivibrator, as amplified by transistor 388, isapplied to terminal 3 of gate 366, thus providing two positive inputs atthis gate, the one previously applied through resistor 364 to terminal 5and the present output of the multivibrator applied to terminal 3.Terminal 4 of this gate is connected to the junction of resistors 390and 392. At this junction positive timing pulses appear, being appliedthrough capacitor 346 from pin 13 of connector 360. These timing pulsesare generated in the following manner:

Positive 18 volts from the power supply is applied to the left terminalof a timing photodiode 394. The right terminal of this diode isconnected through pin 21 of connector 360 to the base of an amplifiertransistor 396. The amplifier signal is taken from the emitter of thistransistor and applied to the base of transistor 398, connected in whatis generally termed a paraphase amplifier circuit. The timing photocell394 is illuminated by the timing lamp 332, through the shutter 108,connected to the main shaft which blocks the light during 180 of theshaft revolution. When illuminated, the resulting current through thephotodiode, amplified by transistor 396, causes the transistor 398collector current to drop to zero, therefore the voltage previouslyexisting across resistors 400 and 402 decreases to zero at this time. Itis evident that two symmetrical square waves of opposite polarity aregenerated at the collector and emitter of transistor 398. The DCcomponent of voltage appearing at the emitter is removed by the couplingcircuit consisting of capacitor 404 and resistor 406 and the signal isapplied through pins 19 of connector 360, 10 of connector 328, and pin Mof cable 330 to one section of FOR.- REV. controller switch 60, which isin the forward position as shown. The inverted output from transistor398 collector is applied through pin 22 of connector 360, through pin 11of connector 328, pin R of cable 330 to the other terminal of theFOR-REV. switch. In the position shown therefore, the common terminal ofthe FOR-REV. switch applies a signal taken from the emitter oftransistor 398 through pin S of cable 330, 12 of connector 328, to pin13 of connector 360. This square wave appearing at terminal 13 isdifferentiated by a short RC time constant circuit consisting ofcondenser 408 and resistor 390. Therefore at the junction of resistors390 and 392 are positive and negative pulses of relatively shortduration. The negative pulses have no effect on any of the circuits towhich they are applied and may be ignored. The positive pulses, however,are effective and are defined as timing pulses. AND"-gates 410, 412,414, 416 and 418 and OR-gates 420 and 422, output terminals 3, 6, 11, 8,8, l2 and 6, respectively, are negative when all gate inputs aresimultaneously positive. Conversely, it can be stated that if any gateinput is negative the output will be positive. The presence of apositive timing pulse at pin 4 of gate 412 results in a negative pulseat pin 6, since positive inputs had previously been established at pinsand 3. The resulting negative pulse appearing at the output pin 6 isapplied to pin 2 of gate 420 resulting in a positive output from thisgate appearing at terminal 12. This positive output triggers transistor424 into conduction. This transistor and transistor 426 make up amonostable multivibrator with an output pulse adjustable in durationfrom approximately to 25 milliseconds, by varying the value of resistor428. This output is amplified by transistor 430 and applied throughresistor 432 to the base of transistor 434, a switching power transistorwhich effectively grounds the lower terminal of front shuttle solenoid234 through resistor 436 for the duration of the pulse generated by themultivibrator transistor 424 and 426. At the conclusion of this pulse,the voltage at the collector or transistor 434 will rise fromessentially zero to the plus 28 volt power supply voltage. This rise iscoupled through resistor 438 and capacitor 440 and applied through diode442 to the base of transistor 444, one of the transistors in themultivibrator consisting of transistors 374 and 376. The resultingpositive voltage at the base will turn off transistor 376, restoring themonostable multivibrator to its stable state concurrent with thetrailing edge of the pulse supplied to the front shuttle solenoid. Inthe manner described, depressing the Single Frame Front push button, 90,has allowed only a single properly timed pulse of the desired durationto be applied to the front shuttle solenoid, moving a single frame ofthe front film in the forward direction as selected by the FOR-REV.switch. In a similar manner a single frame of rear film may be moved.Depressing single frame rear switch 68 applies 18 volts DC from switch70 common to pin Z of cable 330, to pin 2 of connector 304, to pin 8 ofconnector 360 where this voltage is applied through resistor 444 as oneof three inputs required at pin 9 of gate 416. This same voltage isapplied through diode 446 and capacitor 370 to the single framemultivibrator, consisting of transistors 374 and 376, causing it togenerate a positive output from the isolating amplifier transistor 388in a manner identical to that previously described for the single framefront function. This output is applied to pin 11 of gate 416. At pin 10,timing pulses described as appearing at the junction of resistors 390and 392 are applied. Therefore, at pin 8 of gate 416, a negative pulsewill appear, which, applied to pin 4 0f the 422 gate, results in apositive pulse at pin 6 of this gate, applied through resistor 448 tothe base of transistor 450. This transistor and transistor 452 alongwith transistors 454 and 456 make up a multivibrator power amplifiercombination for the rear shuttle solenoid 254 identical to thecombination of transistors 424, 426, 430 and 434 for the front solenoid.Therefore, a single pulse will be delivered from the collector oftransistor 456, which will drive the rear shuttle solenoid. Therefore, asingle pulse will be delivered from the collector of transistor 456,which will drive the rear shuttle solenoid in a manner identical to thatdescribed for the front solenoid. The positive trailing edge of thesolenoid pulse appearing at the collector of transistor 456 is appliedthrough resistor 48, capacitor 460 and diode 442 to the base oftransistor 376 to reset the single frame multivibrator to its stablestate in a manner identical to that previously described for front filmoperation.

CONTINUOUS OPERATION Either the front or rear film may be drivencontinuously at a speed ranging from one through 24 frames per seconddetermined by the setting of speed control switch 67 in the remotecontrol unit. To initiate film motion, the normally open push buttonswitch 64 in the remote control unit is depressed. Positive 18 volts DCsupplied to the common terminal of this switch from the power supplywill then be supplied through its normally open contact through pin E ofcable 330, pin 5 of connector 328 to pin 11 of connector 360. Thispositive voltage is applied through isolating diode 464 to the gateterminal of a silicon controlled rectifier 466. The anode of thisrectifier, connected to pin 12 of connector 360, is supplied with apositive 18 volts through the normally closed stop switch 66, in theremote control unit. When the positive gate signal appears, rectifier466 is driven into conduction, and characteristically will remainconducting even though the gate signal is subsequently removed. Thepositive voltage at pin 12 of connector 360 is thus supplied toresistors 468 and 470 in series to DC common. This voltage may beremoved if desired by momentarily depressing the normally closed stopswitch 66 in the remote control unit, removing the voltage supplied tothe anode of rectifier 466, reducing its current to zero, and restoringit to the nonconducting state. The voltage supplied from the cathode ofdiode 466 to resistor 468 is taken from the wiper of potentiometer 472,through pin 10 of connector 360, 3 of connector 328, through pin C ofcable 330 to the common terminal of speed switch 67 in the remotecontrol unit. This switch connects a number of resistors as required, toestablish the desired film transport speed by selecting the chargingcircuit resistance for 474, the timing capacitor in a unijunctionoscillator circuit. Timing pulses appearing at the junction of resistors390 and 392, previously described, are applied through capacitor 476 tothe base of amplifier transistor 478. This transistor normally operatesin a cut off condition, therefore only the positive portion of thetiming pulses will cause it to conduct to saturation, providing constantamplitude negative timing pulses at the base 2 lead of transistor 480.These timing pulses synchronize the conduction of the unijunctionoscillator, whose frequency would otherwise be determined only by the RCtime constant consisting of capacitor 474 and resistance selected byspeed switch 67 in the remote control unit. Component values are chosento provide input pulse to output pulse ratios from 1:1 to 24:1. Thepositive unijunction oscillator circuit output pulses appear at thejunction of resistors 482 and 484 and are applied to pin 12 of gate 414and pin 2 of gate 410. The other input terminal 1 of the latter gate isconnected through pin 4 of connector 360, pin 4 of connector 304 and pinb of cable 330 to a terminal on the Front-Rear switch 58. In theposition shown on the schematic, this terminal is open, therefore thereis no electrical connection to input terminal 1 of gate 410 which allowsit to assume a positive state, the output, terminal 3, therefore assumesthe negative state, for each positive pulse applied to terminal 2 fromthe counter circuit. These negative pulses are applied to terminal 13 ofgate 420, which functions as an OR gate with inverter, and delivers apositive output pulse at pin 12 for each negative pulse appearing at itsinput. Resistor 486, connected from this terminal to plus 5 volts,provides additional output current. The positive output pulse, appliedthrough resistor 488 to the base of multivibrator transistor 424, willdevelop a pulse whose duration is controlled by resistor 428, amplifiedby transistor 430, and applied to the front film solenoid 234, movingthe film one frame for each counter pulse, in a manner identical to thatpreviously described under single frame front operation. For continuousfilm motion of the rear film, switch 58, in the remote control assembly,is placed in the rear position. In this position, input terminal 1 ofgate 414 is ungrounded and assumes a positive potential. Counter outputpulses appearing at the junction of resistors 482 and 484 are applied tothe other input terminal 12 of gate 414. The simultaneous positiveinputs at these two terminals result in a negative output pulseappearing at the output terminal 11, which in turn is applied to pin 5of gate 422, providing a positive pulse at its output terminal 6, whichin a manner identical to that previously described under single framerear operation, will trigger the rear film multivibrator, whoseamplified signal drives the rear solenoid 254 to move the rear film oneframe for each pulse.

CUING FUNCTION The cue lamp 494, which is illuminated under allconditions, is arranged to illuminate front cue photocell 496 or rearcue photocell 498 whenever a transparent cue spot appears in the opaquesound track area of the corresponding film. When a cue appears on thefront film it allows light from the cue lamp to illuminate photocell496. Conduction of this photocell applies a positive voltage throughresistor 500 to the base of amplifier transistor 502. Conduction fromthis transistor provides a low-resistance path to DC common for thecondenser 474 charging current supplied through the speed switchresistance in the remote controller unit. This prevents the voltage onthis capacitor from rising to a value sufficient to provide an outputpulse from transistor 480, therefore no counter output pulses appear atthe junction of resistors 482 and 484 as long as the front photocell 496remains illuminated. Depressing the single front button 70 will cause asingle frame of front film to move the cue mark away from photocell 496,cutting off the illumination and allowing continuous motion of the filmto resume. In similar manner, depressing the start switch 64, in theremote control unit, although having no effeet on transistor 466, whichis already conducting, will cause a positive voltage to be appliedthrough diode 464 and the upper section of switch 58 to pin y of cable330, to pin 0 of connector 360, initiating the single frame front filmmotion in a manner identical to that obtained from operation of thesingle front switch 70. In similar manner, if switch 58 is in the rearposition, an additional positive pulse through diode 464, obtained bydepressing start switch 64, is applied to the line used to initiatesingle frame operation, thus moving film and restoring continuous filmmotion which had been previously halted by the presence of a front filmtransparent cue spot.

When a transparent cue spot appears on the rear film, cue lamp 494 willilluminate the rear cue photocell 498, applying a positive voltagethrough resistor 504 to the base of amplifier transistor 506. Theamplified current from this transistor appearing across resistance 508causes input terminal 9 of gate 418 to go positive. The other inputterminal, terminal 10, is connected to the output of gate 422, terminal6. This purse, as previously described, is used to initiate rearsolenoid pulse and move the rear film one frame for each such pulse.Each such output pulse of gate 422 will also appear inverted at theoutput of gate 418 as long as input terminal 9 is maintained positive bythe action of the rear cue photocell. Thus, every pulse moving the rearfilm will appear at the output terminal 8 of gate 418, which in turn isconnected to the input of gate 420 terminal 1 and cause a frame of frontfilm to move. As long as the rear cue photocell 498 is illuminated, anyrear film pulse appearing at the output of gate 422 will also appear atthe output of gate 418 and drive the front film.

FILM SPOOLING Operation of the takeup and supply reel drive motors 148and 126, respectively, is described as follows: For reverse operation,effected by switch 60, relay 510 is deenergized, as shown, relaycontacts 3 and 4 connect the normally closed contacts of switches 166and 170 to the AC common terminal, 1, of transformer 308. Functionswitch 72, when placed in position 3, the run position, supplies voltsappearing at terminal 4 of transformer 308, through contacts 7 and 10 ofthe power relay 512, to the leads 151 and 129, respectively, to takeupmotor 148 and supply motor 126. These motor are split field reversiblemotors having split field coils 148 and 127, respectively. Voltageapplied between their leads 151 and 129 at the top or bottom of thesplit field coils 149 and 127 will cause them to rotate in forward orreverse directions. If the film loop controlled by the takeup motorbecomes too small, loop switch 170, is operated from the position shownby the takeup sensing arm to a condition where the common and normallyclosed contacts are connected together. This connects the bottom coillead of the takeup motor to AC common. Since 120 volts is applied to thelead 151 of this motor, it will rotate the takeup reel spindle in thecounterclockwise direction paying out additional film and returningswitch to the position shown and restoring the loop to normal size. Thecircuit through switches 168 and 172 are inoperative in this position ofswitch 60, because of the operation of relay 510. If the projector isbeing operated in the forward direction, relay 510 will be energized andthe AC common will appear at terminal 5, providing a ground for thenormally closed contacts of switches 168 and 172. When takeup loopsensing switch 172 is operated from the position shown, the

top coil lead of the takeup motor will be connected to AC common,causing the motor to rotate in a clockwise direction, taking up excessfilm and maintaining a constant loop size. The supply reel spindle motoris operated by switches 166 and 168 in a manner identical to thatdescribed for the operation of the takeup reel motor. With relay 510deenergized, as shown, excessive loop size will allow the spring-loadedsensing guide 134 to operate switch 166 and cause the supply motor tooperate in the takeup direction by virtue of the AC common connection toits bottom lead of coil 127. Similarly, in the forward direction, ACcommon connection is provided for the top coil lead through switch 168in the position shown, and contacts 3 and 5 of relay 510 in theenergized position, causing the supply reel spindle to rotate in the payout direction, increasing the loop size in accordance with film motion.

REWIND After film has been run through the projector and the program iscompleted, it is necessary to rewind all the film back into the supplyreel. This is accomplished as follows: With no film passing over thesensing arms, the sensing arm switches are positioned as follows: switch166 to NO; switch 170 to NC; switch 168 to NC; switch 172 to NO. Whenfunction switch 72 is placed in the rewind position, relay 510 will bedeenergized since there is no 28 vDC available through section A of thefunction switch. Neither the bottom or top coil lead of takeup motor 148is connected to AC common. The bottom lead of coil 127 of supply motor126 is connected through switch 166 and NC contacts, through contacts 4and 3 of relay 510 to AC common. The lead 129 of the supply reel motoris connected through function switch 72 section C, common to 120 voltsAC causing the supply reel motor to rotate in a takeup directionrewinding the film from the takeup to the supply reel. Takeup reelspindle is provided with a friction clutch mechanism to allow thespindle to rotate during the rewind operation. Capacitors 514, 516, 518and 520, in combination with resistors 522, 524, 526 and 528, placedacross switches 170, I66, I72 and 175, respectively, are used to reducesparking of the switch contacts. To accommodate both clockwise andcounterclockwise wound film, a reversing switch 530 is provided in thefield of supply motor 126.

OPERATION The projector is capable of simultaneous projection of twosuperimposed front and rear 16 mm. films, located in planes 0.03 inchesapart, controlled manually remotely by the operator as well asautomatically by cue marks on the film. The front film capacity is, forexample, 400 feet. The rear film is generally formed in a continuousloop for projection and/or control of the front film, and for example,may be 6 feet of film (240 frames).

Film is transported at any of 18 accurate selectable rates between oneand 24 frames per second, in either the forward or reverse direction.Reversing action is instantaneous and may be done with film in motion atany speed.

The remote operating controls on the remote controller 54 include STARTand STOP buttons 64 and 66, PROJECTOR ON-OFF switch S6, FORWARD-REVERSEselector switch 60, FRONT-REAR film selector switch 58, CUE ON-OFFswitch 62, and FRONT and REAR SINGLE FRAME advance buttons 70 and 68.Utilizing thesecontrols it is possible to advance either the front orrear film, as selected, in either the forward or reverse direction, oneframe at a time, continuously at the preselected speed, orautomatically.

The function switch 72 located on the projector panel allows theoperator to select the LOAD-UNLOAD condition which opens the film gatesto allow film to be inserted or removed, the RUN condition whichtransfers control to the Remote Controller unit, or- REWIND, for rapidrewinding of the film reel. An OFF position is provided which removesall power from the equipment. The pilot lamp 312 indicates when power isapplied.

Both front and rear films utilize cue marks 300 in the area normallyoccupied by the sound track, which are used to control the film motion.When a cue mark appears on the front film, all film motion stops. Motionis restarted by depressing the START button. When a cue mark appears onthe rear film, motion does not stop, but the front film will move oneframe in the same direction, in synchronism with the next rear filmadvance. In this manner it is possible for the rear film to control theadvance of the front film in any desired manner.

Continuous dwell on any frame is possible without damage to the film,reduction in screen brightness or defocusing of the projected image. Thechange from one frame to the next occurs instantaneously with nointervening dark screen line. Flickerless perfonnance is assured byusing a flicker frequency higher than standard for motion pictureprojectors. A highefiiciency optical system assures adequate screenbrightness with minimum heat from a 250 watt low-voltage lamp 104. A

high-resolution, field corrected 2 inch F 1.5 projection lens assures aprojected image with superior focus and resolution.

The projector operates between 105 and 125 volts. Power consumption isnominally less than 400 watts.

The front film is loaded by placing a full reel of film on the reelspindle 122 with the round hole in the reel hub next to the projectorbody.

Any empty takeup reel is then placed on the spindle takeup 146, with thesquare hole in the reel next to the projector body.

The supply reel drive dog is left in the disengaged (up) position, toallow the reel to rotate freely, and pull sufficient film off the supplyreel to thread into the takeup reel loading slot. Manually rotate thetakeup reel in a clockwise direction for several turns in order tosecure the film.

The takeup reel shaft has a friction slip clutch and can be rotated byhand, the supply reel shaft, however, cannot be rotated and should notbe forced. For this reason the supply reel drive dog has been left inits open position to allow the reel to rotate freely around the shaft,while loading.

Set the function switch 72 on the body of the projector to theLoad-Unload position. Set the projector switch 56 on the controller tothe off position.

Starting from the takeup reel, thread film along the threading pathmarked on the projector panel, through the film gate and back to thesupply reel. Rotate the supply reel manually to take up any excesslength of film and engage the supply reel drive dog in the supply reelslot.

Turn the function switch to the run position and press the film down inthe gate to make sure it is properly engaged. Film is engaged when anupward pull will not dislodge it from the film gate.

Select the desired speed with the speed control switch 67 at the top ofthe controller. Set the PROJ. switch to the On position. The projectormotor should start and the lamp illuminate. Select for direction inswitch 60 on the controller.

To initiate film motion, depress the controller start button 64. To stopfilm motion, depress the stop button 66. To move the film one frame at atime, depress the single frame front button 70. To stop film which hasbeen prepared with special cue marks, turn the cue switch 62 to the onposition. To reverse direction of film motion, select rev. position onswitch 60. Operation of the film switch 58 to either the front or rearposition will not effect film motion unless there is a film loaded inthe rear film gate. This mode of operation is covered below.

For loading film loops in rear film gate, set function switch 72 on theprojector panel to Load. Push film loop down in rear film gate, sprocketholes down. Thread loop toward rear of projector, inside the loop guiderails. Set function switch to Run and check loop to insure properengagement in the film gate. To run a loop, the film switch 58 on thecontroller is placed in the rear position. The controller switches willnow operate the rear film. The presence of a cue spot on the rear filmwill cause the front film to move automatically. As when using frontfilm only, the presence of a front film cue, will cause all film motionto stop automatically. Motion is restarted by depressing the Startbutton.

For elevation adjustment, loosen the elevation locking knob by rotatingslightly in the counterclockwise direction. Raise the front of theprojector by hand to the desired position and lock in place by rotatingthe elevation knob clockwise.

Rewinding is most easily accomplished if the film is not allowed to runcompletely off the supply reel. To remove film from the gate, thefunction switch 72 on the projector panel must be set to the Load-Unloadposition. The film will now slide up clear of the gate. Disengage thefilm from the gate and guide rollers and rotate the takeup reel in theclockwise direction to take up excess film. Turn the function switch tothe rewind position. Film will be rewound on the supply reel. When filmis completely rewound, tum function switch to off, disengage the supplyreel drive dog, and remove the reel and film from the projector.

Various changes and modifications may be made within this invention aswill be readily apparent to those skilled in the art. Such changes andmodifications are within the scope and teaching of this invention asdefined by the claims appended hereto.

What is claimed is:

l. A film projector comprising a housing, projection lamp and lens,means for advancing a film past said lamp and means for supplying filmfrom a supply source to said advancing means, said supply meanscomprising a sensing means responsive to the pressure on the film tovary the rate of feed of film from said supply source said film beingfed from the supply source to the advancing means in a path comprising alooped segment leading to the advancing means, said sensing meansoperable upon decrease in the size of the loop to initiate the feed fromthe supply source, and operable upon increase in the size of the loop toreverse the feed.

2. The film projector of claim 1 in which the sensing means comprises asensing member engageable with the film being fed to said advancingmeans.

3. The film projector of claim 2 in which the sensing member isconnected to a switch means responsive to the movement of said sensingmember to control the rate of feed of said film.

4. The film projector of claim 3 in which the switch means is connectedto a reversible motor connected to a supply reel of film.

5. The film projector of claim 1 in which means are provided for takingup film after it advances past the lamp, said means comprising a takeupsensing means responsive to the pressure on the film to vary the rate offeed of film to a film takeup means.

6. The film projector of claim 5 in which the takeup means comprises areversible motor driven takeup reel.

7. The film projector of claim 1 in which the film is fed from thesupply source to the advancing means in a path comprising a loopedsegment leading to the advancing means, said sensing means operable upondecrease in the size of the loop to increase the feed rate from thesupply source.

8. The film projector of claim 7 in which the sensing includes a sensingarm engaged by the film loop, said arm being engageable with a pair ofswitches selectively operable to energize a supply reel motor in aforward or reverse direction to feed out film or take up film.

9. The film projector of claim 4 in which a manually operated switch isprovided to reverse the operation of said motor to accommodate clockwiseand counterclockwise wound supply reels.

10. The film projector of claim 4 in which means are provided for takingup film after it advances past the lamp, said means comprising a takeupsensing means responsive to the pressure on the film to increase therate of feed of film to a reversible motor driven takeup reel.

11. The film projector of claim 10 in which a manually operated switchis provided to reverse the operation of the supply motors to accommodateclockwise and counterclockwise wound supply reels.

1. A film projector comprising a housing, projection lamp and lens,means for advancing a film past said lamp and means for supplying filmfrom a supply source to said advancing means, said supply meanscomprising a sensing means responsive to the pressure on the film tovary the rate of feed of film from said supply source said film beingfed from the supply source to the advancing means in a path comprising alooped segment leading to the advancing means, said sensing meansoperable upon decrease in the size of the loop to initiate the feed fromthe supply source, and operable upon Increase in the size of the loop toreverse the feed.
 2. The film projector of claim 1 in which the sensingmeans comprises a sensing member engageable with the film being fed tosaid advancing means.
 3. The film projector of claim 2 in which thesensing member is connected to a switch means responsive to the movementof said sensing member to control the rate of feed of said film.
 4. Thefilm projector of claim 3 in which the switch means is connected to areversible motor connected to a supply reel of film.
 5. The filmprojector of claim 1 in which means are provided for taking up filmafter it advances past the lamp, said means comprising a takeup sensingmeans responsive to the pressure on the film to vary the rate of feed offilm to a film takeup means.
 6. The film projector of claim 5 in whichthe takeup means comprises a reversible motor driven takeup reel.
 7. Thefilm projector of claim 1 in which the film is fed from the supplysource to the advancing means in a path comprising a looped segmentleading to the advancing means, said sensing means operable upondecrease in the size of the loop to increase the feed rate from thesupply source.
 8. The film projector of claim 7 in which the sensingincludes a sensing arm engaged by the film loop, said arm beingengageable with a pair of switches selectively operable to energize asupply reel motor in a forward or reverse direction to feed out film ortake up film.
 9. The film projector of claim 4 in which a manuallyoperated switch is provided to reverse the operation of said motor toaccommodate clockwise and counterclockwise wound supply reels.
 10. Thefilm projector of claim 4 in which means are provided for taking up filmafter it advances past the lamp, said means comprising a takeup sensingmeans responsive to the pressure on the film to increase the rate offeed of film to a reversible motor driven takeup reel.
 11. The filmprojector of claim 10 in which a manually operated switch is provided toreverse the operation of the supply motors to accommodate clockwise andcounterclockwise wound supply reels.